Observations

Description

Valves are broadly lanceolate, with apices protracted to broadly rounded. The axial area is narrow and straight, forming a narrow, linear to ovoid central area. The raphe is lateral and undulate, with large, rounded external proximal ends and hooked external distal ends. Striae are radiate, with the 1st or 2nd stria at each apex parallel or, rarely, convergent. Within a stria, the marginal areola are large and coarsely arranged. The middle portion has areola comparatively smaller and rounded, and the areolae near the axial area form two rows per stria. The central area has large, round, isolated puncta. The smallest striae at the apices are multiseriate throughout their length.

Valves are broadly lanceolate with apices protracted to broadly rounded. The raphe is lateral and undulate. Within a stria, the marginal areolae are large and more coarsely arranged. The middle valve has areolae comparatively smaller and rounded. Central area has large, round isolated puncta. The smallest striae at the apices are multiseriate throughout their length.

Compare

The large size and distinct structure of this species makes it easy to distinguish from other naviculoid diatoms.

Citations

Kociolek, J.P. and Thomas, E.W. (2010).Taxonomy and ultrastructure of five naviculoid diatoms (class Bacillariophyceae) from the Rocky Mountains of Colorado (USA), with the description of a new genus and four new species.
Nova Hedwigia 90:195-214.10.1127/0029-5035/2010/0090-0195